With the fast development of network technologies and diversified network communication services, the number of subscribers is continuously increasing, which requires higher network bandwidth. The current network bandwidth fails to meet the requirements of the subscribers, and therefore, network congestion inevitably occurs.
When the network congestion occurs, a network device discards a part of data packets according to a certain packet discard policy. The current packet discard policies include a tail drop policy and an intelligent packet discard policy. The tail drop policy is to discard new-arrival data packets directly without considering the priority difference of the data packets when a buffer queue is fully occupied. The intelligent packet discard policy is an improvement to the tail drop policy, which is based on the perception of the services, and selectively discards some data packets that are not important or are with low priorities. For example, in the video transmission field, B-frame data packets are preferentially discarded because this type of data packets has small influence on the display of the entire image, and I-frame or P-frame data packets are not discarded if possible, thereby bringing better visual experience for a terminal user.
However, the packets discarded according to the intelligent packet discard policy are also lost packets for a receiving end. According to current transport protocols such as a Real-time Transport Protocol/RTP Control Protocol (RTP/RTCP), the receiving end requests a transmitting end to retransmit lost packets once the packet loss occurs. The retransmitted data packets cause delay, increase the processing load on the transmitting end, and occupy a great deal of link bandwidth, thereby leading to further network congestion.